BOISE, Idaho (AP) — A federal judge in Idaho says the U.S. Forest Service broke the law when it didn't craft rules to govern snowmobile travel, handing a victory to powder-loving backcountry ski enthusiasts in national forests across the country.

U.S. Magistrate Judge Ronald Bush ruled that the Forest Service must re-visit regulations designating areas of use and non-use by off-road vehicles in a way that includes snowmobiles. Some forests opted to exempt snowmobiles when the rules were revised in 2005.

The Idaho-based Winter Wildlands Alliance argued that the agency's failure to cover the machines was leading to conflicts between snowmobilers and backcountry skiers. Alliance director Mark Menlove says the ruling is a monumental victory. Bush ordered the Forest Service to write a new rule consistent with the executive order within 180 days.